Nikon 10×50 Aculon A211 Binoculars Review: Recommended Product

Optics

The Aculon 10x50s, manufactured by Nikon, employ standard 50mm doublet objective lenses with a relatively fast focal ratio. Notably, there is no Extra-low Dispersion (ED) glass incorporated in these binoculars. However, the crown and flint glasses utilized in the objective lenses are indisputably of exceptional quality. This top-tier glass material is consistently used throughout the construction of these binoculars.

The prisms within the Aculon 10x50s are fabricated from BaK-4, or Barium Crown glass. This type of glass is renowned for being superior compared to the more economical BK-7 glass that is commonly found in many entry-priced binoculars. The BaK-4 prisms are meticulously engineered to fully transmit the entire aperture of the 50mm objectives to the eyepieces without cropping it down to a square shape. This is a considerable advantage, as a square shaped remaining exiting pupil (and thus essentially a stopping-down effect on the front aperture, reducing performance)  is often the result when using more conventional binoculars.

Nikon claims that the “Eco-glass” used in the Aculon 10x50s is environmentally friendly. However, it’s important to note that the term “Eco-glass” essentially indicates that Nikon doesn’t use toxic chemicals in the manufacturing process of the crown and flint glass, a practice that is fairly standard across the industry.

The Aculon 10x50s have multi-layer coatings applied to all optical surfaces. These coatings play a pivotal role in ensuring the sharpest possible images. They help in mitigating glare and eliminating contrast issues, which can often be a problem, especially in binoculars with smaller apertures that are used for diverse applications.

In terms of light-gathering capability, a pair of binoculars with a 50mm aperture, such as the Aculon 10x50s, have a light-gathering power comparable to that of a 3 to 4-inch telescope. While they don’t have the ability to provide close-up views of the moon, planets, or double stars due to their fixed 10x magnification, they offer the advantage of a wide field of view.

The Aculon 10x50s have an apparent field of view of 65° at the eyepiece, which corresponds to a 6.5° true field at 10x magnification, often expressed as 341 feet at 1,000 yards. This is fairly typical for a pair of 10×50 binoculars, and the 65-degree apparent field makes for an immersive viewing experience, though it isn’t as all-encompassing as one might experience with super-wide-angle eyepieces.

What sets the Aculon 10x50s apart from many cheaper 10x50s is the sharpness across the entire field of view, thanks to Nikon’s quality eyepiece design. In contrast, many lower-priced 10×50 binoculars with a similar field of view often exhibit distortions at the edges or even chromatic aberration. 

Mechanics

The focusing system on the Aculon 10x50s is based around a center dial, which is common among most binoculars. Like any center-focused binocular, these binoculars are equipped with a diopter adjustment on one of the eyepieces. This allows for fine-tuning and compensating for any differences in vision between the user’s eyes.

Nikon has ensured that internal reflections of these binoculars are kept to an absolute minimum. This is achieved through a combination of expertly designed internal baffling and the utilization of high-quality materials. The entire body of the binocular is adeptly baffled on the inside, which drastically reduces stray light and internal reflections. This feature is essential for providing crystal-clear views without the hindrance of glare.

Another noteworthy feature of the Aculon 10x50s is the design of the eye cups. Unlike the folding or rolling-up designs found in other models, the eye cups on these binoculars employ a twist-up mechanism. This design not only ensures a more durable build but also contributes significantly to user comfort. The twist-up eyecups are more secure than a fold-up design, reducing the chances of accidental adjustment (e.g. popping inward), and tend to have a longer lifespan. The Aculon 10x50s offer 12mm of eye relief with the eye cups rolled down, which is enough for most glasses wearers if on the short side for this task.

The Aculon 10x50s are ruggedly built with rubber armor for protection and are fully waterproof. However, it is worth noting that they are not purged with any gas internally. If they are subjected to a severe impact, such as being dropped, it may affect their collimation (alignment of optical axes), necessitating that they be sent back to the manufacturer for servicing. However, with careful handling, these binoculars can last a lifetime. 

Mounting Recommendations

While quite a few individuals find it possible to hold 10×50 binoculars steady, others may find it advantageous to mount them on a monopod or tripod. At about 2 lbs., the Aculon 10x50s aren’t particularly heavy compared to other 10x50s, but there’s nothing wrong with providing extra support. It is generally recommended to use a monopod instead of a tripod for these binoculars due to the greater convenience and lower cost of a monopod. Alternatively, a parallelogram mount can also be used, but it’s important to note that they can be expensive in comparison to the relatively modest price of the Nikon Aculon 10×50 binoculars. Whichever mounting solution is chosen, a metal tripod adapter is required to attach these binoculars to a 1/4-20 stud.

Should I buy Used Nikon Aculon 10×50 Binoculars?

When it comes to purchasing a used pair of Nikon Aculon 10×50 binoculars, or any used binoculars for that matter, there are some concerns to keep in mind. One primary concern is damage or misalignment of the internal prisms. The Nikon Aculon 10×50 binoculars do not have gas purging, so you don’t have to worry about gas leaks. However, this also means that there is no gas inside to prevent internal corrosion.

Damage to the internal prisms, objective lenses, or eyepieces should be quite evident, even to an inexperienced observer. Misalignment of the prisms, also known as collimation issues, can be detected if the view through the binoculars doesn’t seem synchronized between the two eyepieces, especially when observing something close by. Additionally, when examining a used pair, make sure that the focusing mechanism moves smoothly. This is indicative of a well-maintained pair of binoculars.

Alternative Recommendations

Internally, the Aculon 10x50s may share similarities with other binoculars in the same category, such as the Bushnell Legacy WP 10x50s, and possibly some models from Orion. This doesn’t make them inferior, but it’s worth considering the price point. While the Aculon 10x50s were initially priced over $100, it seems that their competitors with similar features have leveled out around the same price range.

Under $125

• The Celestron Skymaster 15×70 binoculars have a larger aperture compared to the Nikon Aculon 10x50s, and also feature similar BAK-4 prisms. However, due to their weight and higher magnification, it is almost necessary to use a tripod or monopod to stabilize them during use. Additionally, it has been observed that there are often quality control issues concerning these binoculars, particularly with collimation. Some units have been reported to be out of collimation straight out of the box or after minimal use, which is something to be wary of.
• The Celestron Skymaster 12×60 binoculars are also commendable. With 12x magnification and a smaller 60mm aperture, they might still be used handheld by some individuals, though employing a monopod or parallelogram mount is advisable for the best experience. The quality control issues that are apparent with the larger Skymaster 15x70s don’t seem to be as frequent with the 12×60 model.
• The Zhumell 12×70 Astronomy Binoculars borrow optics and mechanics from the Skymaster 15x70s but offer a wider and steadier view, and 12x magnification is more tolerant of frequent collimation problems.
• The SVBONY SV-206 10×50 binoculars boast a significantly wider field of view than the Nikon Aculon 10x50s, standing at 7.5°. Moreover, they are more affordable. However, there are trade-offs in terms of durability and optical quality with these binoculars, including noticeable loss of sharpness toward the edges of the field of view.
• The Celestron Cometron 7×50 binoculars are an option to consider if you’re on a tighter budget, Though they have little to no rubber armor, poor coatings, and BK7 prisms, they perform surprisingly well compared to the Aculon 10x50s, especially given that they are about a third of the price. The UpClose G2 10×50 binoculars are similar in design to the Cometron, but with 10x magnification, they have slightly less vignetting due to the higher power.

Over $125

• The Celestron Skymaster Pro 15x70s, are an upgrade from the regular Skymaster 15x70s. They feature semi-ED glass, a wider field of view, better exterior armor, fewer quality control issues with collimation, and sharper optical performance. The option to use winged eyecups is also a notable feature. However, these binoculars are considerably more expensive and, due to their size and magnification, still necessitate the use of a tripod or monopod.
• The Celestron Skymaster DX 8×56 binoculars present a unique option, offering slightly more aperture, and consequently, better performance than a typical 50mm model while maintaining a comparable form factor. The increase in aperture to 56mm significantly enhances light-gathering power, and these binoculars provide impressive views. However, at 8x magnification, the exit pupil is relatively large, which might not be ideal in areas with excessive ambient light.
• The Celestron Skymaster DX 9×63 binoculars are slightly larger in aperture and thus offer brighter views than the 8×56 model. Similar to the Skymaster 12x60s, their usability for handheld operation depends on the user, though the 9x magnification makes them somewhat more forgiving in this respect. Like the Skymaster DX 8×56, these binoculars feature BAK-4 prisms and sharp optics.

What can you see?

Like any reputable pair of 10×50 binoculars, the Aculon 10x50s excel in observing large deep-sky objects, such as nebulae and open star clusters. With these binoculars, under a dark sky, you can marvel at the intricate details in the Cygnus area of the Milky Way, observing objects like the North America and Pelican Nebulae, M29, the Cygnus star cloud, and more. Open clusters such as M11, M35, and the Double Cluster appear spectacular. Nebulae like Orion, Rosette, and Lagoon are also awe-inspiring sights through the Aculon 10x50s.

Globular star clusters are generally visible as faint, fuzzy spots, with the exception of Omega Centauri. Due to its exceptional brightness and size relative to other globular clusters, Omega Centauri can be faintly resolved into individual stars.

Galaxies are often too dim and small to observe in great detail through 10×50 binoculars, especially if you are situated near any light pollution. However, you should still be able to discern the dust lanes in the Andromeda Galaxy and observe groupings like the Leo Triplet, M82 and M81, the Virgo Cluster, and M110, a satellite galaxy of Andromeda.

Wide double stars such as Albireo, as well as the two pairs in Epsilon Lyrae, can be resolved owing to their relatively large separation.

Closer to home, the Aculon 10x50s can also reveal some solar system sights. For instance, craters and large geological features on the moon, including lunar maria or “seas”, are visible. Additionally, when the moon is in its waxing crescent phase, you can observe “earthshine”, which is the dimly lit part of the moon illuminated by sunlight reflecting off the Earth.

Venus can be observed with its phases, although holding the binoculars steady is essential. Mars, though visible, will only appear as a tiny dot with no discernible details. Jupiter, on the other hand, is more rewarding; not only can its disk be seen, but also all four of the Galilean moons – Io, Europa, Ganymede, and Callisto. Saturn is somewhat indistinct, often appearing oval-shaped without clearly defined rings, though its moon Titan is visible nearby. Uranus and Neptune can be seen even from suburban skies through the Aculon 10x50s, but they of course are not resolved into disks without the use of 100x magnification or more.